The present invention relates to apparatus for inserting an intraocular lens through a small incision into an eye, to methods for making such apparatus and to methods for inserting an intraocular lens into an eye. More particularly, the invention relates to an apparatus which has enhanced lubricity and is useful for inserting a foldable intraocular lens into an eye, to methods for making such apparatus and to methods using such apparatus to insert a foldable intraocular lens into an eye.
An intraocular lens (IOL) is implanted in the eye, for example, as a replacement for the natural crystalline lens after cataract surgery or to alter the optical properties of (provide vision correction to) an eye in which the natural lens remains. IOLs often include an optic, and preferably at least one flexible fixation member or haptic which extends from the optic and becomes affixed in the eye to secure the lens in position. The optic normally includes an optically clear lens. Implantation of such IOLs into the eye involves making an incision in the eye. It is advantageous, to reduce trauma and speed healing, to have an incision size as small as possible.
IOLs are known which are foldable (deformable) so that the IOL can be inserted through a smaller incision into the eye. A substantial number of instruments have been proposed to aid in inserting such a foldable lens in the eye.
Many of the prior art IOL insertion systems load and/or fold the lens at the distal end, that is at the end closest to the eye or the end inserted into the eye. Such "distal loading" systems often disadvantageously include a space consuming loading component at or near the distal end of the system which causes the distal end to be relatively large. This relatively large distal end makes inserting the IOL through a small incision more difficult, if not impossible. Systems which fold and load the IOL proximally of the distal end provide certain advantages, such as reduced stress on the IOL and/or inserter, relative to "distal loading" systems.
However, whether using a distal loading or proximal loading system, one factor which limits the size of the inserter tube involves the inserter tube itself. For example, the material from which the inserter tube is made, for example, polypropylene and the like polymeric materials, may not be compatible or otherwise susceptible to causing optics, for example, made from silicone polymeric materials, to pass through relatively small hollow spaces. For example, the injector tubes may be made of materials, in particular polymeric materials, which have insufficient lubricity to facilitate the passage of a folded IOL through the tube.
As a result of this lack of lubricity, the hollow space of the injector tube must be made relatively larger to accommodate the folded intraocular lens. This is detriment since, as noted above, it is advantageous to have the smallest possible incision for insertion of the IOL. In addition, if one were to use a small diameter tube to pass the IOL, excessive force might be needed to pass the IOL through the small hollow space thereby increasing the risks of damaging the IOL and, in extreme cases, even damaging the eye into which the IOL is placed.
One approach that may be considered is to use a lubricity agent, for example, such as conventional visco-elastic agents, in the hollow space of the tube to facilitate passing the IOL through the insertion apparatus. However, such lubricity agents in and of themselves occupy valuable space, thereby at least partially defeating the purpose of using such agents. Also, such lubricity agents often end up in the eye, thereby creating the risk of causing trauma and/or irritation and/or damage to the eye.
It would be advantageous to provide straightforward IOL insertion apparatus and methods for using same which facilitate the passage of folded IOLs through the apparatus in a controlled manner without using excessive force.